Container package having improved seal

ABSTRACT

A retortable container package includes a container and a composite closure. The container includes a 60 to 140 taper formed on an inboard side of the finish portion. A raised channel of the closure&#39;s insert disk includes a substantially flat top portion and an inner wall sloped at approximately the same angle as the taper angle. A sealant in the channel is deformed upon application of the closure onto the container such that the sealant forms a seal between the closure and each of (i) an outer wall of the finish portion proximate the lip, (ii) the lip, and (iii) the taper. Upon retorting, the seal between the container&#39;s taper and the channel inner wall is enhanced by the contraction of the finish portion diameter. A corresponding method includes an application step.

CROSS REFERENCE TO RELATED APPLICATIONS

The subject matter disclosed herein claims priority under 35 U.S.C. § 119(e) to provisional U.S. patent application Ser. No. 60/755,031, filed Dec. 30, 2005, entitled “CONTAINER PACKAGE HAVING IMPROVED SEAL” which is hereby incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

This invention relates to a combination container and closure and more particularly to a container and closure package configuration for improving sealing, and related methods.

BACKGROUND OF THE INVENTION

Container threads may be formed during injection molding of a preform or may be formed during blow molding of an injection molded or extruded preform. The process for forming blow-molded threads often includes forming an intermediate article that includes structure above the container finish. For example, U.S. Pat. No. 6,228,317 discloses a moil structure formed during blow molding that is severed from the container.

Regardless of the method of forming a container and its threads, composite closures are well known for use for products that are hot filled, retorted, pasteurized, or undergo like heat treatment. A goal of the present invention is to provide a package including a container and composite closure having improved sealing capabilities and corresponding method.

SUMMARY OF THE INVENTION

A retortable container package is provided that includes a container and a composite closure. The container includes a finish portion that terminates in a circular lip. A taper is formed on an inboard side of the finish portion and merges into the lip. The taper in transverse cross section forms an angle of 6° to 14° from vertical.

The closure includes a circular skirt, an insert disk, and a sealant. The insert is disk-like and includes a peripheral bead, a raised channel inboard of the peripheral bead, and a circular center portion inboard of the channel. The raised channel includes an outer wall, a substantially flat top portion, and an inner wall sloped at approximately the same angle as the taper angle. Preferably, the outer wall is sloped.

The sealant is disposed in the channel, and is at least partially deformed upon application of the closure onto the container such that the sealant forms a seal between the closure and each of (i) an outer wall of the finish portion proximate the lip, (ii) the lip, and (iii) the taper. After retorting, the seal between the finish portion taper and the channel inner wall is enhanced by the contraction of the finish portion diameter. Preferably, the sealant is groove-less prior to application of the closure to the container. After retorting, the seal between the finish portion taper and the channel inner wall is enhanced by the contraction of the finish portion diameter.

The taper preferably is spaced apart from the channel inner wall by a gap of between 0.005″ and 0.015″ prior to retorting, and preferably, after retorting between 0.00″ and 0.015″, more preferably between 0.002″ and 0.010″, and even more preferably, between 0.003″ and 0.008″. The slope of the inner wall of the channel preferably defined a first point on the inner wall proximate the top portion and a second point on the inner wall proximate the center portion.

Preferably, the inner wall of the channel is curved, and an uppermost portion of the container lip is substantially planar. The container finish portion may include a radiused portion between the lip, and the container lip may be arcuate.

An uppermost portion of the container lip preferably forms and angle of between 1° and 12° from the horizontal, more preferably between 2° and 80°, and more preferably between 2° and 5°.

A method of forming a container package is provided that includes providing a moil-trimmed container that includes a reamed taper on an interior finish portion, providing a composite closure, applying the closure to the container such that the sealant is deformed by the container finish portion and forms a seal between the closure and each of (i) an outer wall of the finish portion proximate the lip, (ii) the lip, and (iii) the taper; and retorting the container package such that the container finish decreases in diameter to diminish a gap between the finish portion taper and the channel inner wall to enhance the seal therebetween. The container may have blow-molded threads.

The preferred composite closure employed in the method includes a circular skirt, an insert, and a sealant. The disk-like insert includes a peripheral bead, a raised channel inboard of the peripheral bead, and a circular center portion inboard of the channel. The raised channel includes an outer wall, a substantially flat top portion, and an inner wall sloped at approximately the same angle as the taper angle. The sealant is disposed in the channel. The composite closure also may encompass other features described above.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 (Prior Art) is a cross section view of a container package including a container and composite closure;

FIG. 2 is a cross section view of a container package including a container and composite closure illustrating an embodiment of the present invention; and

FIG. 3 is an enlarged view of a portion of the package shown in FIG. 2.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Referring to FIG. 1 to illustrate potential problems with prior art container packages and related methods, a prior art container and composite closure package 110 includes prior art container 112 and composite closure 140. Container 112 includes threads 122 formed on an outboard side of the finish and a lip 126 at the uppermost portion of the finish.

Closure 140 includes a plastic band 142 and a metal disk 144. Disk 144 includes a peripheral bead or curl 160, a downwardly facing raised channel 162, and a center portion 164. A sealant 174 is disposed in channel 162. Preferably, sealant 174 is groove-less prior to application of the closure to the container.

Container threads 122 are formed by (preferably) blow-molding or injection molding. A projection 113, which protrudes substantially radially inwardly from lip 126, is the lower portion of a structure formed to locate a blade in a moil trimming operation. U.S. Pat. No. 6,228,317, which is incorporated herein by reference in its entirety, illustrates forming the container lip and an inward projection such as projection 113.

Because lip 126 is pressed into sealant 174, projection 113 inhibits or prevents the flow of sealant 174 toward the inner surface of the container neck, which diminishes or prevents sealing or sealing contact at the container neck, especially at the inner surface.

Referring to FIG. 2 to illustrate an embodiment of the present invention, a container and closure package 10 includes a container 12 and composite closure 40. Closure 40 is provided to illustrate an embodiment of the present invention, and the present invention is not limited to any particular type or material of closure, nor is it limited to any particular closure configuration, and includes for example closures formed of one piece, unless the structure is expressly recited in the claim.

Container 12 includes a sidewall 14 that forms an enclosed bottom portion (not shown in the figures). A finish portion 16 extends upwardly from sidewall 14 and includes, in transverse cross section, an outboard side 18 and an inboard side 20. Container threads 22 are formed on finish outboard side 18. Threads 22 of container 12 preferably are formed by a blow-molding process. Above the threads, outboard side 18 includes an upper outer sidewall 24 that is sloping toward a lip 26. Preferably, container 12 is formed of a thermoplastic, such as polypropylene, or other material suitable for retorting or like heat treating.

Lip 26 includes an outer curved transition portion 30 and an inner curved transition portion 32. Preferably, an upper face 34 is disposed between curved transition portions 30 and 32. Upper face 34 may be substantially planar in transverse cross section or may be curved. Transition portions 30 and 32 may be defined by a single radius or multiple radii or may be a substantially flat bevel or like configuration lacking curved surfaces. Transition portion 30 need not have the same configuration as that of transition portion 32. Inner transition portion 32 yields to a taper 36, which merges into the inner surface 38 of the finish portion.

As best shown in FIG. 3, upper face 34 is sloped inwardly and downwardly at an angle C and preferably is straight in transverse cross section. Preferably, angle C is between 1° and 12° from a horizontal line H, more preferably, between 2° and 8°, most preferably between 2° and 5°. The present invention also encompasses an upper face of the finish having a substantially horizontal top as well as an upper face formed of a curve or curves, multiple straight portions, or a combination thereof (not shown in the figures). In such alternative configuration, the angle C may be measured from an outermost point of the upper face to an innermost point of the upper face.

Preferably, taper 36 as shown in FIGS. 2 and 3 is formed by a reaming process that removes projection 113. Taper 36 is substantially flat in transverse cross section or frustoconical and inclined from a vertical line at an angle A. Preferably, angle A is between 6° to 14°. The present invention encompasses configurations of the portion between transition portion 32 and container inner surface 38 other than flat, such as curves, multiple flat surfaces, or a combination thereof. Such alternative configurations (not shown in the figures) are encompasses by the term “taper” as used herein. For such alternative configurations, the angle A may be measured between an upper point where the taper meets transition portion 32 and a lower point where the taper meets inner surface 38.

Composite closure 40 includes a band 42, which preferably is formed of a plastic, and an insert disk 44, which preferably is formed of a metal. Band 40 includes a skirt 46 and a flange 48 extending radially inwardly from an upper portion of skirt 46. A tamper evident band 50 extends from a lower portion of skirt 46. An inboard surface of skirt 46 includes closure threads 52 and, preferably, a retaining bead 54 that is spaced apart from disk 44 when the closure is in the applied state.

The space between pads 56 formed on an underside of flange 48 and retaining bead 54 enables disk 44 to float during application and removal of closure 40. Floating disk 44 enables the initial unscrewing of closure 40 to occur in sequence. First, a torque is required to disengage closure threads 54 from container threads 22, then a torque is required to brake the frangible bridges of the tamper evident band 50, and then retaining bead 54 urges upwardly against disk 44. The present invention is not limited to sequential opening configurations, but such configuration is employed for illustration. For example, the present invention may be employed with closure/container combinations that employ ratchets.

Disk 44 includes a peripheral bead 60, and downwardly-opening channel 62 disposed radially inward of bead 60, and a circular center portion 64 disposed radially inward of channel 62. Channel 64 is formed by an outer wall 66, a top 68 extending from outer wall 66, and an inner wall 70 extending from top 68. Preferably, top 68 is linear in transverse cross section. Top 68 may be sloped inwardly and downwardly at an angle such that top 68 forms a frustum of a cone. Preferably, the angle C is between 1° and 12° from a horizontal line H, more preferably, between 2° and 8°, most preferably between 2° and 5°. Preferably, the angle of slope of top 68 matches angle C of container upper surface 34, and the shape in transverse cross section of top 68 matches that of upper surface 34. The present invention also encompasses a channel having a substantially horizontal top and a curved top (not shown in the figures).

As shown in FIG. 2, channel inner wall 70 forms an angle B with the vertical. Preferably, inner wall 66 is straight-sided in transverse cross section. The invention encompasses a curved or irregularly-shaped wall, in which configuration angle B may be measured between a first point on inner wall 66 proximate a transition to top 68 and a second point on inner wall 66 proximate center portion 64. Preferably, channel inner wall angle B is substantially the same as that angle A of taper 36. As best shown in FIG. 2, a taper 36 is spaced apart from channel inner wall 66 by a gap G. Gap G for the embodiment illustrated may be 0.000 to 0.020″, preferably between 0.00″ and 0.015″, more preferably between 0.002″ and 0.010″, and even more preferably between 0.003″ and 0.008″. The container often is not circular after retorting and gap G may vary around the circumference. Accordingly, the dimensions for gap G are averages. The present invention, however, is not limited to any particular gap dimension or configuration, unless specifically recited in the claims.

Sealant 74 forms an outside seal against an outboard side of finish portion 16 (preferably on transition 30 and outboard side 18), a top seal against upper face 34, and an inboard seal against an inboard side of finish portion 16 (preferably on transition 32 and taper 36). The inside seal is enhanced because projection 113 from the moil trimming operation has been removed.

Because package 10 may be subjected to retorting, pasteurizing, or other sterilizing or heat-treating step, the plastic material of container 12 may shrink upon application of heat while the metal disk will maintain its dimensions. The inner radius, shown schematically as dimension R in FIG. 2, of container 12 will diminish after such heating step. Dimension G will decrease, thereby enhancing the inner seal.

The present invention also encompasses a method of forming a container package having an improved seal. In this regard, container 12 is provided with a moil (not shown in the figures) that is removed by a moil trimming operation. U.S. Pat. No. 5,617,768, which is incorporated by reference in its entirety, discloses apparatus and methods for moil trimming. Then the interior portion of the container neck is reamed to form taper 36 on an interior portion of the finish.

Composite closure 40 is applied to container 12 such that the sealant 74 is deformed by container finish portion 16 such that sealant 74 forms a seal against each of (i) an outer wall of the finish portion proximate the lip, (ii) the lip, and (iii) the taper, as described above. Container package 10 is retorted or otherwise heat treated such that container finish 16 decreases in diameter to diminish gap G between finish portion taper 36 and channel inner wall 70 to enhance the seal therebetween.

Aspects of container package, such as the retorting process or like heat treating process, the formulation and processing of the container such that it is suitable for reforming, manufacturing and well-known structure and functional aspects of the closure, methods and apparatus for the reaming processes, are understood by persons familiar with container and/or closure manufacturing, and any of such processes may be applied to produce the structure described herein.

The embodiments described herein are employed to illustrate the present invention. The present invention, however, is not limited to the particular structure disclosed herein. 

1. A retortable container package comprising: a container including a finish portion that terminates in a circular lip, a taper is formed on an inboard side of the finish portion and merges into the lip, the taper in transverse cross section forms an angle of 6° to 14° from vertical; and a composite closure capable of being applied to the container, the closure including: a circular skirt; a disk-like insert including a peripheral bead, a raised channel inboard of the peripheral bead, and a circular center portion inboard of the channel; the raised channel including an outer wall, a substantially flat top portion, and an inner wall sloped at approximately the same angle as the taper angle; and a sealant disposed in the channel, the sealant being partially deformed upon application of the closure onto the container such that the sealant forms a seal between the closure and each of (i) an outer wall of the finish portion proximate the lip, (ii) the lip, and (iii) the taper; whereby after retorting, the seal between the finish portion taper and the channel inner wall is enhanced by the contraction of the finish portion diameter.
 2. The container package of claim 1 wherein the taper is spaced apart from the channel inner wall by a gap of between 0.005″ and 0.015″ prior to retorting.
 3. The container package of claim 2 wherein the gap is between 0.00″ and 0.015″ after retorting.
 4. The container package of claim 3 wherein the gap is between 0.002″ and 0.010″ after retorting.
 5. The container package of claim 4 wherein the gap is between 0.003″ and 0.008″ after retorting.
 6. The container package of claim 1 wherein where the slope of the inner wall of the channel is defined a first point on the inner wall proximate the top portion and a second point on the inner wall proximate the center portion.
 7. The container package of claim 1 wherein the inner wall of the channel is curved.
 8. The container package of claim 1 wherein an uppermost portion of the container lip is substantially planar.
 9. The container package of claim 8 wherein the container finish portion includes a radiused portion between the lip.
 10. The container package of claim 1 wherein an uppermost portion of the container lip is arcuate.
 11. The container package of claim 1 wherein an uppermost portion of the container lip forms and angle of between 1° and 12° from the horizontal.
 12. The container package of claim 11 wherein an uppermost portion of the container lip forms and angle of between 2° and 8° from the horizontal.
 13. The container package of claim 1 wherein an uppermost portion of the container lip forms and angle of between 2° and 5° from the horizontal.
 14. The container package of claim 1 wherein the sealant is groove-less prior to application of the closure to the container.
 15. The container package of claim 1 wherein the channel outer wall is sloped.
 16. The container package of claim 1 wherein the container is formed of a polypropylene.
 17. A method of forming a container package comprising the steps of: providing a moil-trimmed container that includes a reamed taper on an interior finish portion; providing a composite closure that includes: a circular skirt; a disk-like insert including a peripheral bead, a raised channel inboard of the peripheral bead, and a circular center portion inboard of the channel; the raised channel including an outer wall, a substantially flat top portion, and an inner wall sloped at approximately the same angle as the taper angle; and a sealant disposed in the channel; applying the closure to the container such that the sealant is deformed by the container finish portion such that the sealant forms a seal between the closure and each of (i) an outer wall of the finish portion proximate the lip, (ii) the lip, and (iii) the taper; and retorting the container package such that the container finish decreases in diameter to diminish a gap between the finish portion taper and the channel inner wall to enhance the seal therebetween.
 18. The method of claim 17 wherein the step of providing the container includes providing a container having blow-molded threads.
 19. The method of claim 17 wherein the taper in cross section forms an angle of 6° to 14° from vertical.
 20. The method of claim 19 wherein the taper is spaced apart from the channel inner wall by a gap of between 0.005″ and 0.015″ prior to retorting.
 21. The method of claim 20 wherein the gap is between 0.00″ and 0.015″ after retorting.
 22. The method of claim 20 wherein the gap is between 0.002″ and 0.010″ after retorting.
 23. The method of claim 20 wherein the gap is between 0.003″ and 0.008″ after retorting.
 24. The method of claim 17 wherein an uppermost portion of the container lip is substantially planar.
 25. The method of claim 24 wherein the container finish portion includes a radiused portion between the lip.
 26. The method of claim 17 wherein an uppermost portion of the container lip is arcuate.
 27. The method of claim 17 wherein an uppermost portion of the container lip forms and angle of between 1° and 12° from the horizontal.
 28. The container package of claim 11 wherein an uppermost portion of the container lip forms and angle of between 2° and 8° from the horizontal.
 29. The method of claim 17 wherein an uppermost portion of the container lip forms and angle of between 2° and 5° from the horizontal.
 30. The method of claim 17 wherein the sealant is groove-less prior to application of the closure to the container.
 31. The container package of claim 1 wherein the container is formed of a polypropylene. 